1949 Nanoscale investigation of diffusion and solid state reactions of Ni/Si and Ag/Au thin film systems PhD Thesis Shenouda Shanda Shenouda Fam Supervisor Prof. Dr. Dezső L. Beke Department of Solid State Physics Faculty of Science and Technology PhD School in Physics University of Debrecen Debrecen, Hungary 2015 Ezen értekezést a Debreceni Egyetem Természettudományi Doktori Tanács Fizikai Tudományok Doktori Iskolájának Szilárdtestfizika és anyagtudomány programja keretében készítettem a Debreceni Egyetem természettudományi doktori (PhD) fokozatának elnyerése céljából. Debrecen, 2015. Shenouda Shanda Shenouda Fam I prepared this PhD thesis in the framework of the Solid State Physics and Materials Science program of the PhD School in Physics for the PhD title on Science at the University of Debrecen. Debrecen, 2015. Shenouda Shanda Shenouda Fam Tanúsítom, hogy Shenouda Shanda Shenouda Fam doktorjelölt 2012- 2015 között a fent megnevezett Doktori Iskola Szilárdtestfizika és anyagtudomány programjának keretében irányításommal végezte munkáját. Az értekezésben foglalt eredményekhez a jelölt önálló alkotó tevékenységével meghatározóan hozzájárult. Az értekezés elfogadását javasolom. Debrecen, 2015. Prof. Dr. Beke Dezső Témavezető I certify that Shenouda Shanda Shenouda Fam candidate for the PhD degree did his work under my supervision in the framework of the Solid State Physics and Materials Science program between 2012- 2015. The candidate achieved a determining role to the results in this thesis by his self-supporting and creative activity. I propose to accept the dissertation. Debrecen, 2015. Prof. Dr. Dezső L. Beke Supervisor Nanoscale investigation of diffusion and solid state reactions of Ni/Si and Ag/Au thin film systems Értekezés a doktori (Ph.D.) fokozat megszerzése érdekében a Fizika tudományágban Desirtation to obtain the doctoral (Ph.D.) degree in Physics Írta: Shenouda Shanda Shenouda Fam, fizika MSc Prepared by: Shenouda Shanda Shenouda Fam, MSc in Physics Készült a Debreceni Egyetem Fizikai Tudományok Doktori Iskolája Szilárdtestfizika és anyagtudomány programja keretében University of Debrecen, Doctoral School of Physics within the framework of Solid State Physics and Material Science program Témavezető/Supervisor: Prof. Dr. Dezső L. Beke A doktori szigorlati bizottság/The doctoral exam committee: elnök/Chairman: Dr. Ferenc Kun …………………….. tagok/Members: Dr. Gábor Erdélyi …………………….. Dr. István Groma …………………….. A doktori szigorlat időpontja/The doctoral exam date: 2015 June 09 Az értekezés bírálói/The thesis reviewers: Dr. …………………….. …………………….. Dr. …………………….. …………………….. A bírálóbizottság /The committee for the defense: Chairman: Dr. …………………….. …………………….. Members: Dr. …………………….. …………………….. Dr. …………………….. …………………….. Dr. …………………….. …………………….. Dr. …………………….. …………………….. Az értekezés védésének időpontja/Date of the defense of the thesis: 2015. ……………… … . I dedicate this Doctor of Philosophy thesis to my mother, my brother Mina and to the spirit of my father. Also, I dedicate this thesis to my future wife. Contents Contents Page List of abbreviations and symbols 1 Motivation 7 Chapter 1: Introduction 9 1.1. Atomic fluxes and Fick law ........................................ 9 1.2. Equations for diffusion ............................................... 12 1.2.1. Bulk diffusion ................................................... 13 1.2.1.1. Chemical or interdiffusion .................. 13 1.2.2. Grain boundary ................................................. 18 1.3. Solid state reactions .................................................... 20 1.3.1. Nucleation and growth of layers and diffusional kinetics ..................................................... 20 1.3.2. Solid state reactions in thin film systems at low temperatures ........................................................ 24 Chapter 2: Literature review 31 Chapter 3: Experimental techniques and tools 39 3.1. DC Magnetron Sputtering .......................................... 39 3.2. High vacuum and Hydrostatic pressure furnaces ....... 42 3.3. Secondary Neutral Mass Spectrometry (SNMS) ........ 43 3.4. Profilometer ................................................................ 45 3.5. X-ray Diffraction (XRD) ............................................ 46 3.6. Transmission Electron Microscope (TEM) ................ 46 Chapter 4: Results and discussion 47 4.1. Production of NiSi phase by grain boundary diffusion induced solid state reaction between Ni2Si and Si(100) substrate ................................................................ 47 4.2. Kinetics of shift of individual interfaces in Ni/Si system during low temperature reactions .......................... 60 4.3. Grain boundary intermixing in Ag/Au thin film system and nanoscale Kirkendall porosity formation ....... 71 Conclusions 79 Summary 81 Summary in Hungarian (Összefoglalás) 83 References 85 Publications 93 Acknowledgment 97 List of abbreviations and symbols (CMOS) Complementary metal-oxide-semiconductors (MSD) Metallic source/drain (MOSFETs) Metal-oxide-semiconductor field effect transistor (ULS IC) Ultra-large-scale integrated circuits (GB) Grain boundary (DIGM) Diffusion induced grain boundary motion (DIR) Diffusion induced recrystallization Chemical potential of A material Chemical potential of pure A material Flux of A atoms Flux of B atoms Onsager coefficient Boltzmann constant Absolute temperature Atomic fraction (concentration) of A atoms 2 List of abbreviations and symbols Atomic fraction (concentration) of B atoms Atomic volume Atomic volume of A atoms Atomic volume of B atoms Activity coefficient of A atoms Number of A atoms per unit volume Number of B atoms per unit volume Thermodynamic factor Intrinsic diffusion coefficient of A material Intrinsic diffusion coefficient of B material Number of atoms or moles per unit area Number of atoms in plane 1 per unit area Number of atoms in plane 2 per unit area Distance between neighboring atoms (the lattice distance) Jump frequency Jump frequency from plane 1 to 2 Jump frequency from plane 2 to 1 Average jump frequency Jump frequency across the interface Brownian diffusion coefficient of A material Vertical coordination number List of abbreviations and symbols 3 Pure chemical driving force Convective velocity Pressure driving forces Pressure Diffusion coefficient Melting temperature Kirkendall-velocity ⃗ Flux of A atoms in the laboratory frame ⃗ Flux of B atoms in the laboratory frame ̃ Chemical or interdiffusion coefficient ̃ Darken interdiffusion coefficient ̃ Nernst-Planck interdiffusion coefficient Boltzmann new variable Time Distance in direction, position of the interface Distance in direction M Matano plane Shift of the interface Shift velocity of a plane or interface Thickness of the growing phase Growth rate constant An intermediate phase 4 List of abbreviations and symbols Thickness of grain boundary Grain size Grain boundary diffusion coefficient Effective diffusion coefficient g Grain boundary fraction Parameter ( ) Parameter ( √ ) Parameter ( ) √ ̅ Laterally averaged (tracer) composition JI Flux of A atoms across the A/AB interface Shift velocity of the A/AB interface Proportionality factor Composition width of the interface Composition range where the AB phase exists Difference of the number of A atoms in two neighbouring planes per unit surface -( ) Concentration gradient Critical thickness at which the transition from linear to parabolic happens Film thickness Concentration of A atoms in the GB Concentration of B atoms in the GB List of abbreviations and symbols 5 Grain boundary diffusion coefficient of A material Grain boundary diffusion coefficient of B material Parameter ( ) Proportionality factor between the GB composition and the composition deposited by the moving boundary Darken like interdiffusion coefficient in the GB Nernst-Planck like interdiffusion coefficient in the GB Coefficient of segregation Height of GB step Burgers vector (GBDIREAC) Grain boundary diffusion-induced reaction layer formation (RTA) Rapid thermal annealing (SNMS) Secondary neutral mass spectrometry (TEM) Transmission electron microscopy a-Si Amorphous-Si c-Si Crystalline-Si (DCS) Differential scanning calorimetry (XRD) X-ray diffraction (DC) Direct current (FWHM) Full width at half maximum Wavelength Angle of diffraction 6 List of abbreviations and symbols Average migration distance Equilibrium composition of the growing phase Average concentration Activation energy Growth constant Activation energy obtained from the temperature dependence of linear growth constant Linear growth constant Volume fraction Resistance Conductivity Volume Corrected time after subtracting the time required to fill the boundary Shift of the A/AB interface Shift of the AB/B interface Saturation value of concentration Motivation Nowadays, the increased demand for minimizing the size of any kind of device became technologically a chief challenge. This field of science plays a vital role in the present technologies. The down scale can affect significantly the properties of the product and improve their performance. Thus, the nanoscale investigation of diffusion and solid state reactions in thin film systems is very important for many technologies and applications such as complementary metal-oxide-semiconductors (CMOS), metallic source/drain (MSD) MOSFETs and in the ultra-large-scale integrated circuits (ULS IC). These investigations contribute to better understanding of the details of the reactions. Silicides are very important contact materials in such applications.